The present invention relates to a new and improved construction of apparatus for detecting non-combusted fuel components in exhaust gases of a heating installation and also pertains to a method for operating the aforesaid apparatus.
The efficiency of an oil heating installation is dependent to a large extent upon the adjustment of the burner and the infeed of the air. In order to realize maximum efficiency the burner should be adjusted such that there is produced an air-fuel mixture possessing an approximately stochiometric oxygen-fuel ratio or a small excess of oxygen.
If the air infeed is too small then the exhaust gases contain non-combusted carbon. On the other hand, if the air infeed is too large then the flame possesses a relatively small temperature and from the fuel there are formed from so-called crack reactions unsaturated hydrocarbons which then likewise partially escape without being burned along with the exhaust gases. In both instances the exhaust gases contain unburned or non-combusted fuel components, so that the efficiency decreases. If combustion proceeds with an excess of air then additionally the thermal yield is reduced owing to the smaller flame temperature.
Usually the burner is optimumly adjusted at the time that the heating installation is installed. However, during operation changes can occur, resulting in a deviation from the optimum conditions. For instance, it is possible that the filter in the oil infeed line, the burner head or the air suction line become clogged. Further, the draft conditions in the flue can alter due to contamination and for other reasons. These changes generally result in a decrease in the efficiency of the system. On the other hand, this leads to an increased fuel consumption and, on the other hand, to a considerable pollution of the environment. The latter is especially of significance since if there is an incomplete combustion there are also formed noxious substances, for example carbon monoxide.
Heretofore the checking of heating installation was carried out by skilled persons associated with the heating industry, for instance, chimney sweeps or other skilled mechanics who visually checked, after a longer period of operation, the deposition of carbon black and tar. Due to this visual checking it was possible to draw certain conclusions regarding the operation of the burner. Yet, such visual control is rather subjective and only possible if following each such control there are removed the deposits which have been found. Furthermore, such checking operations can only be carried out at relatively large time intervals.
Additionally, apparatuses are known to the art which consist of a suction pump and a filter head using a paper filter. In order to check the operation of the heating installation the person checking the installation during operation of the burner, sucks exhaust gases produced by the heating installation through the paper filter by means of the pump for a certain period of time. In the event that the exhaust gas contains carbon black due to an insufficient quantity of air being present during combustion then there will be produced a blackening of the filter. This can then be compared with a comparison scale and in turn there can be ascertained the content of carbon black in the exhaust gases. However, if the heating installation is operated with an excess of air then the exhaust gases do not contain carbon black, rather unsaturated hydrocarbons. Such do not blacken the paper filter rather produce a yellow coloration thereon. It is, however, hardly possible from this yellow coloration of the paper filter to somewhat exactly determine the hydrocarbon content of the exhaust gases. To arrive at a reliable quantitative determination of the quantity of hydrocarbons present in the exhaust gases there must be carried out a quantitative chemical analysis or a chromatographic test. A reliable determination of the unburned fuel components which are present in the exhaust gases by means of this state-of-the-art apparatus is therefore extremely complicated. Since to carry out a quantitative-determination there is required in any event a person making such control this type of checking of the heating installation can only be accomplished at relatively large time intervals.